Highest Tariff May Reach 511.75%! Countdown to Final Ruling on Anti-Dumping Duties for Chinese MDI

On April 1, 2026, several members of Congress from Michigan jointly sent a letter to the Chair of the U.S. International Trade Commission (USITC), publicly pressuring the agency to impose high anti-dumping duties on Chinese MDI (methylene diphenyl diisocyanate), accusing China of dumping the product at prices far below fair market value, thereby harming the U.S. domestic industry and threatening supply chain security and employment.

The legislators emphasized in the letter: The MDI industry supports nearly 60,000 jobs across the United States, with Michigan being a core production area, and it cannot allow unfair trade to impact domestic manufacturing and job stability.

(Key figure and co-signer: Kristen McDonald Rivet, Democratic U.S. Representative from Michigan; opposes Trump-style across-the-board high tariffs but takes a hard line against China to protect Michigan’s manufacturing, chemical, and automotive supply chains—representing a classic constituency-based industrial protectionist stance.)

Key Timeline of the Case:

April 2, 2026 09:30 | USITC Hearing

By April 27, 2026, the final anti-dumping determination will be announced.

Anti-dumping preliminary determination announcement on MDI, the dumping margin is as follows:

MDI is a core raw material for polyurethane, widely used in construction, automotive, household appliances, thermal insulation materials, and other fields. Amid intense pressure from U.S. political circles and with a final ruling imminent, Chinese MDI exports to the U.S. will face severe tariff barriers; relevant enterprises must closely monitor the ruling outcome and promptly adjust their export strategies and risk mitigation measures.